jeffrey brown reports on the tightening presidential contest. >> brown: barack obama won this state in 2008 by the slimmest of margins with help from a large african-american turnout. four years later in a down economy it looks like his challenge will be even greater. >> woodruff: and we talk with national public radio's greg allen. he focuses on the outreach to hispanics in the tar heel state. >> ifill: then margaret warner updates the investigation into the assault on the u.s. consulate in libya. >> woodruff: we look at new findings showing australia's great barrier reef has lost half its coral in the last 27 years. >> ifill: and we close with snapshots of three of this year's macarthur genius award winners, each with a unique view of war. >> people tend to look at the military, they tend to look at war and they tend to look at conflict as something very black and white. it's not like that at all. >> ifill: that's all ahead on tonight's newshour. major funding for the pbs newshour has been provided by: creating new enriching experiences. through intel's philosophy of "invest you for